Recently, use of computer communication networks and information networks via the Internet is becoming common practice, is spreading and is increasing among general households and enterprises. The most general use may be to form a LAN (Local Area Network) by connecting a LAN cable to a personal computer directly or by using radio waves enabling the network such as the Internet accessible from a computer in the LAN. When the LAN cable is used in such circumstances, the cable that is drawn in the house or office becomes an obstacle against walking or casts a problem from the standpoint of appearance. When the wireless LAN is used, on the other hand, the communication based on the radiation of electromagnetic waves causes a problem of security, such as leakage of information, unauthorized access, etc.
A patent document 1 (Kokai (Japanese Unexamined Patent Publication) No. 2004-7448) and a patent document 2 (Kokai (Japanese Unexamined Patent Publication) No. 2006-19979) are teaching that these problems can be solved by using a two-dimensional communication medium as communication means.
In recent years, an article management using IC tag for RFID is drawing attention as a new network system. In the field of distribution, for example, there has been proposed an art of sticking IC tags for RFID to the products in the step of production in a factory and tracing the flow of the articles in a subsequent route of distribution, offering expectations of rationalization of production, efficiency of distribution management and reduction of cost. In the step of production, a proposal has also been made to record the history information for every movement and work concerning where the parts have passed through, how the parts were worked and to where the parts were shipped. There can be, further, exemplified management of book stock in the libraries as well as management of documents in the offices, management of goods in the stores and management of chemicals in the research facilities, and it is expected that the use of the RFID system will rapidly spread in the future.
However, when the articles are to be managed by using the IC tags for RFID, shelves having a function of antenna must be newly introduced requiring a large system and posing a problem from the standpoint of introducing and installing the system.